JP2010284822A - Recording head and manufacturing method thereof - Google Patents

Abstract

An object of the present invention is to inhibit the movement of an actuator from being hindered, and to prevent the wiring of a flat flexible substrate connected to the actuator from being short-circuited or damaged.
A plurality of lands 58 are formed on a substrate 51. A first insulating coat 65 is formed by screen-printing and completely curing the first insulating epoxy resin on the land 58 in the land area 60 where the land 58 is formed, and the area excluding the periphery thereof. In each hole 65 a of the first cover coat 65, the second insulating epoxy resin is screen-printed and semi-cured to form the second cover coat 66. Then, the actuator unit 21 and the COF 50 are arranged so that the individual bump 136 contacts the land 58 that passes through the semi-cured second cover coat 66 and faces the land 58. The second cover coat 66 is completely cured by applying a heat and pressure treatment.
[Selection] Figure 11

Description

  The present invention relates to a recording head that discharges liquid from nozzles and a method for manufacturing the same.

  As an inkjet head for ejecting ink droplets onto a recording medium such as printing paper, a flow path unit in which a large number of individual ink flow paths including pressure chambers communicating with nozzles are formed, and the volume of each pressure chamber is changed. Some have an actuator that adds ink droplet ejection energy to the pressure chamber. A flat cable for supplying a drive signal for driving the actuator is connected to the actuator. A plurality of lands that are electrically joined to the bumps of the actuator are disposed on the surface of the flat cable. Then, the drive signal output from the driver IC is supplied to each bump of the actuator via the wiring pattern and land of the flat cable. When this flat cable is joined to the actuator, in order to protect the land and the wiring pattern, an uncured thermosetting resin is applied to the surface of the flat cable and heated, so that the semi-cured state covers a plurality of lands. A technique for forming a resin layer is known (see, for example, Patent Document 1). Then, the flat cable is joined to the actuator by pressing the flat cable against the actuator so that the bump penetrates the resin layer and is joined to the land.

Japanese Patent Laying-Open No. 2005-305847 (FIG. 10)

  According to the above-described technology, when a flat cable is joined to an actuator, a foreign object enters between the flat cable and a member that presses the flat cable, so that a part of the flat cable is curved toward the actuator. However, the semi-cured resin layer in the convex portion may come into contact with the surface of the actuator, and a part of the resin layer may adhere to the surface of the actuator. In this case, a part of the adhered resin layer inhibits the movement of the actuator, so that the ink ejection characteristics are deteriorated. In addition, the conductive foreign matter adhering to the semi-cured resin layer may penetrate the resin layer, and the foreign matter may contact between the wires drawn from the land to cause a short circuit or damage the wiring. is there.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a recording head capable of suppressing the movement of the actuator from being hindered, and short-circuiting or damaging the wiring of the flat flexible substrate connected to the actuator, and a manufacturing method thereof. Is to provide.

  The recording head manufacturing method of the present invention includes a flow path unit in which a plurality of nozzles for discharging liquid are formed, and an actuator for discharging liquid from the nozzles, and includes a plurality of individual bumps arranged on a plane. A manufacturing method of a recording head having an actuator and a flat flexible substrate that supplies a drive signal to the individual bumps of the actuator, wherein a plurality of the plurality of the plurality of actuators are formed on a surface of a base material to be the flat flexible substrate. A land forming step for forming a plurality of lands corresponding to the individual bumps, and a first area so as to cover an area excluding the lands and the periphery of the lands in the land arrangement area where the plurality of lands are arranged on the surface. A first insulating material applying step of applying an insulating material; and a first covering layer forming step of forming a first covering layer by curing the first insulating material; A second insulating material application step of applying a second insulating material so as to cover the land and the periphery of the land in the land arrangement region where the first covering layer is formed, and the applied second An arrangement step of placing the flat flexible substrate on the actuator so that the individual bumps penetrate the insulating material and contact the lands, and the applied second insulation material is cured after the arrangement step. And a second coating layer forming step of forming a second coating layer.

  According to the present invention, the land excluding the land and the periphery of the land in the flat flexible substrate is covered with the hardened first coating layer, so that the flat flexible substrate is curved in the arranging step. Even if the first coating layer contacts the surface of the actuator, it is possible to prevent a part of the first coating layer from adhering to the surface of the actuator. Thereby, it can suppress that the motion of an actuator is inhibited. Moreover, it is possible to prevent the conductive foreign matter from penetrating the first coating layer. As a result, it is possible to prevent the conductive foreign matter from coming into contact with the wiring drawn from the land in the land arrangement region to cause a short circuit or damage to the wiring.

  The present invention further includes a semi-curing step of semi-curing the applied second insulating material prior to the arranging step, and in the second coating layer forming step, the semi-cured state is The second covering layer is preferably formed by curing the second insulating material. According to this, since the second insulating material is in a semi-cured state in the arranging step, the second insulating material is likely to stay around the land and the land, and is prevented from moving or dropping to another place. Is done. Thereby, the 2nd coating layer of a desired form can be formed easily.

  At this time, the first insulating material and the second insulating material have thermosetting properties, and in the first coating layer forming step, the first coating material is heated to heat the first coating material. Forming and semi-curing the second insulating material by heating the second insulating material in the semi-curing step; and in the second covering layer forming step, forming the second insulating material in a semi-cured state. It is more preferable to form the second coating layer by further heating. According to this, since it is only necessary to perform heat treatment in both the first covering layer forming step and the second covering layer forming step, the manufacturing cost can be reduced.

  In the present invention, the first insulating material and the second insulating material may be different materials.

  Moreover, in this invention, it is preferable that the said 1st coating layer is higher than the said land on the said surface regarding the direction orthogonal to the said surface. According to this, in the arrangement step, the base material can be pressed with a uniform pressure against the plane of the actuator. Thereby, an individual bump and a land can be made to contact reliably.

  Further, in the present invention, a pattern forming step for forming a plurality of wirings electrically connected to the lands on the surface, and prior to the placement step, the land adjacent to the land placement region, A third insulating material applying step for applying a third insulating material so as to cover a wiring region in which the wiring is arranged; and prior to the arranging step, the third insulating material is cured to form a third covering layer. It is more preferable to further include a third covering layer forming step to be formed. According to this, it can suppress that a conductive foreign material adheres between wirings, and is short-circuited or wiring is damaged.

  At this time, it is more preferable that the second insulating material and the third insulating material are the same material. According to this, the cost of the recording head can be reduced.

  The recording head of the present invention includes a flow path unit in which a plurality of nozzles for discharging liquid is formed, an actuator for discharging liquid from the nozzle, and an actuator having a plurality of individual bumps arranged on a plane; A flat flexible substrate that is fixed to the actuator and supplies a driving signal to the individual bumps. The flat flexible substrate includes a base having a surface facing the plane, a plurality of lands disposed on the surface of the base and electrically bonded to the plurality of individual bumps, and the plurality of lands. An insulating first covering layer that covers the land and the area excluding the periphery of the land, and the individual bumps are penetrated, and the land is surrounded around the land. The second coating layer has a higher hardness than the first coating layer. According to this, since the 2nd coating layer has covered the circumference of a land, it can control that a conductive foreign material adheres between lands, and a short circuit or a land is damaged. In addition, since the second coating layer has a higher hardness than the first coating layer, it is possible to stabilize the electrical bonding state between the individual bumps and the lands and to suppress the loss of flexibility of the flat flexible substrate. be able to.

  According to the present invention, since the land excluding the land and the periphery of the land is covered with the hardened first coating layer in the flat flexible substrate, the flat flexible substrate is bent in the arranging step. Even if one coating layer contacts the surface of the actuator, it is possible to prevent a part of the first coating layer from adhering to the surface of the actuator. Thereby, it can suppress that the motion of an actuator is inhibited. Moreover, it is possible to prevent the conductive foreign matter from penetrating the first coating layer. As a result, it is possible to prevent the conductive foreign matter from coming into contact with the wiring drawn from the land in the land arrangement region to cause a short circuit or damage to the wiring.

1 is a cross-sectional view of an inkjet printer according to an embodiment of the present invention. It is sectional drawing along the width direction of the inkjet head shown in FIG. It is sectional drawing regarding the III-III line | wire shown in FIG. It is an enlarged view of the area | region enclosed with the dashed-dotted line shown in FIG. (A) It is a fragmentary sectional view of the actuator unit shown in FIG. (B) It is a partial top view of an actuator unit. FIG. 3 is a plan view of the COF shown in FIG. 2. It is sectional drawing regarding the VII-VII line shown in FIG. It is a block diagram which shows the manufacturing process of the inkjet head shown in FIG. (A) It is a top view of the base material in the land and wiring pattern formation process shown in FIG. (B) It is a top view of the base material in the soldering resist formation process shown in FIG. (C) It is a top view of the base material in the driver IC mounting process shown in FIG. (A) It is a top view of the base material in the 1st cover coat formation process shown in FIG. (B) It is a top view of the base material in the 2nd insulating epoxy resin printing process shown in FIG. It is a partial expanded sectional view of COF for demonstrating the pressurization heating joining process shown in FIG.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the ink jet printer 101 has a rectangular parallelepiped housing 1a. In addition, a paper discharge unit 31 is provided at the top of the housing 1a. Furthermore, the inside of the housing 1a is divided into three spaces A, B, and C in order from the top. In the space A, four inkjet heads 1 and a transport unit 20 that respectively eject magenta, cyan, yellow, and black inks are arranged. In each of the spaces B and C, a paper feed unit 1b and an ink tank unit 1c that can be attached to and detached from the housing 1a are arranged. In the present embodiment, the sub-scanning direction is a direction parallel to the transport direction when the paper P is transported by the transport unit 20, and the main scanning direction is a direction orthogonal to the sub-scanning direction and along the horizontal plane. Direction.

  Inside the ink jet printer 101, a paper transport path for transporting the paper P from the paper feed unit 1b toward the paper discharge unit 31 is formed (thick arrow in FIG. 1). The sheet feeding unit 1 b includes a sheet feeding tray 23 that can store a plurality of sheets P, and a sheet feeding roller 25 attached to the sheet feeding tray 23. The paper feed roller 25 sends out the uppermost paper P among the plurality of papers P stacked and stored in the paper feed tray 23. The paper P sent out by the paper feed roller 25 is guided to the guides 27 a and 27 b and sent to the transport unit 20 while being sandwiched by the feed roller pair 26.

  The transport unit 20 includes two belt rollers 6, 7, an endless transport belt 8 wound around the rollers 6, 7, and a tension roller 10. The tension roller 10 applies tension to the conveyor belt 8 by being urged downward in the lower loop of the conveyor belt 8 while being in contact with the inner peripheral surface thereof. The belt roller 7 is a driving roller, and rotates clockwise in FIG. 1 when a driving force is applied from the transport motor M through two gears. The belt roller 6 is a driven roller, and rotates clockwise in FIG. 1 as the conveyor belt 8 travels as the belt roller 7 rotates.

  The outer peripheral surface 8a of the conveyor belt 8 is subjected to silicone treatment and has adhesiveness. A nip roller 4 is disposed at a position facing the belt roller 6 with the conveyance belt 8 interposed therebetween on the paper conveyance path. The nip roller 4 presses the sheet P sent out from the sheet feeding unit 1 b against the outer peripheral surface 8 a of the transport belt 8. The paper P pressed against the outer peripheral surface 8a is conveyed rightward in FIG. 1 while being held on the outer peripheral surface 8a by the adhesive force.

  Further, a peeling plate 5 is provided at a position facing the belt roller 7 with the conveyance belt 8 interposed therebetween on the paper conveyance path. The peeling plate 5 peels the paper P from the outer peripheral surface 8a. The peeled paper P is guided by the guides 29a and 29b and conveyed while being sandwiched between the two pairs of feed rollers 28, and is discharged from the opening 30 at the top of the housing 1a to the paper discharge unit 31.

  The four inkjet heads 1 are supported by the housing 1a via the frame 3. The four inkjet heads 1 each extend along the main scanning direction and are arranged in parallel to each other in the sub-scanning direction. That is, the ink jet printer 101 is a line type color ink jet printer in which an ejection region extending in the main scanning direction is formed. The lower surface of each inkjet head 1 is an ejection surface 2a from which ink droplets are ejected.

  A platen 19 is disposed in the loop of the conveyor belt 8 so as to face the four inkjet heads 1. The upper surface of the platen 19 is in contact with the inner peripheral surface of the upper loop of the conveyor belt 8 and supports it from the inner peripheral side of the conveyor belt 8. Thereby, the outer peripheral surface 8a of the upper loop of the conveyor belt 8 and the lower surface of the inkjet head 1, that is, the ejection surface 2a are parallel to each other, and a gap with a predetermined interval suitable for image formation is formed. The gap constitutes a part of the paper transport path. When the paper P transported by the transport belt 8 passes just below the four heads 1, ink of each color is sequentially ejected from each head 1 toward the upper surface of the paper P, and a desired color is applied onto the paper P. An image is formed.

  Each inkjet head 1 is connected to an ink tank 49 mounted on the ink tank unit 1c in the space C. That is, the ink discharged from the corresponding inkjet head 1 is stored in each of the four ink tanks 49. Then, ink is supplied from each ink tank 49 to the inkjet head 1 via a tube (not shown) or the like.

  Next, the inkjet head 1 will be described in detail with reference to FIGS. In FIG. 3, the lower housing 87 is omitted.

  As shown in FIG. 2, the inkjet head 1 includes a reservoir unit 71, a head body 2 including a flow path unit 9 and an actuator unit 21, one end connected to the actuator unit 21, and a driver IC 52 mounted thereon. It has a COF (Chip On Film: flat flexible substrate) 50 and a control substrate 54 to which the other end of the COF 50 is connected. Further, the inkjet head 1 includes an upper housing 86 and a lower housing 87 that form a box surrounding the reservoir unit 71 and the flow path unit 9, and a head cover 55 that surrounds the control substrate 54 above the upper housing 86. have.

  The reservoir unit 71 is a flow path forming member that is fixed to the upper surface of the head body 2 and supplies ink to the head body 2. The reservoir unit 71 is a stacked body in which four plates 91 to 94 are aligned and stacked, and an ink inflow channel (not shown), an ink reservoir 72, and 10 The ink outflow channels 73 are formed so as to communicate with each other. In FIG. 2, only one ink outflow channel 73 appears. The ink inflow channel is a channel into which ink from the ink tank 49 flows. The ink reservoir 72 is an ink reservoir that temporarily stores the ink that has flowed from the ink inflow passage. The ink outflow channel 73 is a channel through which the ink from the ink reservoir 72 flows out, and communicates with the ink supply port 105 b formed on the upper surface of the channel unit 9. The ink from the ink tank 49 flows into the ink reservoir 72 through the ink inflow channel, passes through the ink outflow channel 73, and is supplied to the channel unit 9 from the ink supply port 105b.

  Further, a recess 94 a is formed on the lower surface of the plate 94. The recess 94 a forms a gap 90 with the upper surface of the flow path unit 9. In the gap 90, the four actuator units 21 on the flow path unit 9 are arranged at equal intervals along the longitudinal direction of the flow path unit 9. Further, four openings 90a of the gap 90 are formed in a staggered manner at equal intervals along the longitudinal direction of the reservoir unit 71 on the side surface of the laminate.

  Further, the lower surface of the plate 94 has a convex portion (a portion other than the concave portion 94 a) bonded to the flow path unit 9. An ink outflow channel 73 is formed in the convex portion and communicates with the ink supply port 105b.

  The vicinity of one end of the COF 50 is connected to the upper surface of the actuator unit 21. Further, the COF 50 extends in the horizontal direction from the upper surface of the actuator unit 21 and passes through the opening 90a, and then is bent and bent at a substantially right angle upward, so that the inner wall surfaces of the upper housing 86 and the lower housing 87 It passes through a notch 53 formed in the upper part of the reservoir unit 71 and passes through the notch 53. Further, the COF 50 extends to the left in FIG. 2 above the reservoir unit 71, and is then pulled out from the slit 86 a formed in the upper housing 86 to the upper housing 86. A terminal 50 a (see FIG. 6) disposed at the other end of the COF 50 is connected to the connector 54 a of the control board 54 above the upper housing 86. A driver IC 52 is mounted in the middle of the COF 50. The driver IC 52 is affixed to the upper surface of the reservoir unit 71 and is thermally coupled to the reservoir unit 71. Thereby, the heat generated from the driver IC 52 is transmitted to the reservoir unit 71 to cool the driver IC 52, while the ink viscosity in the reservoir unit 71 is suppressed from being increased by warming the ink in the reservoir unit 71.

  The control board 54 is disposed above the upper housing 86 and controls the driving of the actuator unit 21 via the driver IC 52 of the COF 50. The driver IC 52 generates a drive signal that drives the actuator unit 21.

  Further, the head body 2 will be described with reference to FIGS. 3 and 4. In FIG. 4, for convenience of explanation, the pressure chamber 110, the aperture 112, and the discharge port (nozzle opening) 108 that are to be drawn by broken lines below the actuator unit 21 are drawn by solid lines.

  As shown in FIG. 3, the head body 2 is a laminated body in which four actuator units 21 are fixed to the upper surface 9 a of the flow path unit 9. As shown in FIGS. 3 and 4, the flow path unit 9 has an ink flow path including a pressure chamber 110 and the like formed therein. The actuator unit 21 includes a plurality of actuators corresponding to the pressure chambers 110, and has a function of selectively giving ejection energy to the ink in the pressure chambers 110.

  A total of ten ink supply ports 105 b are opened on the upper surface 9 a of the flow path unit 9 corresponding to the ink outflow flow path 73 (see FIG. 2) of the reservoir unit 71. As shown in FIG. 3, the flow path unit 9 has a manifold flow path 105 communicating with the ink supply port 105b, a sub-manifold flow path 105a branched from the manifold flow path 105, and further branched from the sub-manifold flow path 105a. A large number of individual ink flow paths are formed. As shown in FIG. 4, a discharge surface 2a is formed on the lower surface of the flow path unit 9, and a large number of discharge ports 108 are arranged in a matrix. A large number of pressure chambers 110 having a rhombic planar shape with rounded corners are also arranged in a matrix on the upper surface 9a of the flow path unit 9 (the fixed surface of the actuator unit 21). The ejection ports 108 are arranged at an interval of 600 dpi, which is the resolution in the main scanning direction with respect to the main scanning direction.

  In the present embodiment, 16 rows formed by the pressure chambers 110 arranged at equal intervals in the longitudinal direction of the flow path unit 9 are arranged in parallel in the width direction. The number of pressure chambers 110 included in each pressure chamber row corresponds to the outer shape (trapezoidal shape) of an actuator unit 21 described later, from the long side (lower base side) to the short side (upper base side). It arrange | positions so that it may decrease gradually toward it. The discharge port 108 is also arranged corresponding to this.

  The flow path unit 9 is a laminated body in which a plurality of metal plates made of stainless steel are aligned with each other. A large number of individual ink flow paths 132 are formed in the flow path unit 9 from the manifold flow path 105 to the sub-manifold flow path 105a and from the outlet of the sub-manifold flow path 105a to the discharge port 108 through the pressure chamber 110.

  The ink flow in the flow path unit 9 will be described. As shown in FIGS. 3 to 4, the ink supplied from the reservoir unit 71 into the flow path unit 9 through the ink supply port 105 b is distributed from the manifold flow path 105 to the sub-manifold flow path 105 a. The ink in the sub-manifold channel 105 a flows into each individual ink channel and reaches the ejection port 108 via the pressure chamber 110.

  Next, the actuator unit 21 will be described. As shown in FIG. 5A, the actuator unit 21 includes three piezoelectric sheets 141 to 143 made of a lead zirconate titanate (PZT) ceramic material having ferroelectricity. An individual electrode 135 is formed on the upper surface of the uppermost piezoelectric sheet 141 so as to face the pressure chamber 110. A common electrode 134 formed on the entire surface of the sheet is interposed between the uppermost piezoelectric sheet 141 and the lower piezoelectric sheet 142. As shown in FIG. 5B, the individual electrode 135 has a substantially rhombic planar shape similar to the pressure chamber 110. In plan view, most of the individual electrodes 135 are in the region of the pressure chamber 110. One of the acute angle portions of the substantially rhomboid individual electrode 135 extends outside the pressure chamber 110, and an individual bump 136 electrically connected to the individual electrode 135 is provided at the tip thereof.

  The common electrode 134 is equally grounded in the region corresponding to all the pressure chambers 110. On the other hand, the individual electrode 135 is electrically connected to each output terminal of the driver IC 52 via the COF 50, and a drive signal from the driver IC 52 is selectively supplied.

  Here, a driving method of the actuator unit 21 will be described. The piezoelectric sheet 141 is polarized in the thickness direction. When an electric field is applied in the polarization direction to the piezoelectric sheet 141 by setting the individual electrode 135 to a potential different from that of the common electrode 134, the electric field application portion of the piezoelectric sheet 141 functions as an active portion that is distorted by the piezoelectric effect. A portion including the active portion and sandwiched between the individual electrode 135 and the pressure chamber 110 functions as an individual actuator, and a plurality of actuators corresponding to the number of the pressure chambers 110 are built in the actuator unit 21. . For example, if the polarization direction is the same as the electric field application direction, the active portion contracts in a direction (plane direction) perpendicular to the polarization direction. That is, the actuator unit 21 uses the upper one piezoelectric sheet 141 away from the pressure chamber 110 as a layer including an active portion, and the lower two piezoelectric sheets 142 and 143 close to the pressure chamber 110 as inactive layers. It is a so-called unimorph type actuator. As shown in FIG. 5A, since the piezoelectric sheets 141 to 143 are fixed to the upper surface of the plate 122 that partitions the pressure chamber 110, the electric field application portion of the piezoelectric sheet 141 and the piezoelectric sheets 142 and 143 below the electric field application portion. If there is a difference in the strain in the plane direction, the entire piezoelectric sheets 141 to 143 are deformed so as to be convex toward the pressure chamber 110 (unimorph deformation). As a result, pressure (discharge energy) is applied to the ink in the pressure chamber 110, and ink droplets are discharged from the discharge ports 108.

  In this embodiment, a predetermined potential is applied to the individual electrode 135 in advance, and the individual electrode 135 is once set to the ground potential every time there is a discharge request, and then the potential is applied to the individual electrode 135 again at a predetermined timing. A drive signal to be applied is output from the driver IC 52. In this case, the piezoelectric sheets 141 to 143 return to the original state at the timing when the individual electrode 135 becomes the ground potential, and the volume of the pressure chamber 110 increases as compared with the initial state (a state in which a voltage is applied in advance). Ink is sucked from the manifold channel 105 a into the individual ink channel 132. After that, at the timing when a predetermined potential is applied to the individual electrode 135 again, the piezoelectric sheets 141 to 143 are deformed so that the portions facing the active region protrude toward the pressure chamber 110, and the ink is reduced due to the volume reduction of the pressure chamber 110. The pressure increases, and ink is ejected from the ejection port 108.

  Next, the COF 50 will be described in detail with reference to FIGS. 6 and 7. In FIG. 6, the outer shape of the actuator unit 21 to which the COF 50 is joined is indicated by a broken line. Further, the length of the COF 50 in the vertical direction in the drawing is drawn short. Further, the wiring pattern 59 to be indicated by a broken line is indicated by a solid line. As shown in FIG. 6, the COF 50 has a film-like substrate 51. On the surface of the base material 51, a land region 60 having a substantially trapezoidal planar outer shape substantially identical to that of the actuator unit 21, and extends downward from the land region 60 while adjoining the long side of the land region 60. Wiring area 61 is formed. The land area 60 is an area where a plurality of lands 58 are formed, and is formed corresponding to the individual bump 136 of the actuator unit 21. The wiring area 61 is an area in which the driver IC 52 is mounted in the middle of the wiring area 61 and a plurality of wirings 59 a corresponding to the lands 58 and wirings 59 b corresponding to the driver IC 52 are formed. A terminal 50 a connected to the connector 54 a of the control board 54 is connected to the end of the wiring area 61.

  As shown in FIGS. 6 and 7, in the land region 60, the lands 58 are joined to the individual bumps 136, and a part of the wiring 59 a drawn from the lands 58 is disposed. Further, an insulating first cover coat (first covering layer) made of a first insulating epoxy resin (for example, a solder resist for developing type rigid substrate PSR-4000 FLX series) on the land region 60. 65 is formed. The first cover coat 65 is formed with a plurality of holes 65 a that expose the land 58 and a region excluding the periphery of the land 58. As described above, the first cover coat 65 covers the land 58 except for the land 58 and the periphery of the land 58, that is, a part of the wiring 59 a drawn from the land 58. The height from the surface of the base material 51 according to the first cover coat 65 is higher than that of the land 58. In the present embodiment, the development resist is used from the viewpoint of the accuracy of forming the fine holes 65a, but a thermosetting resist may be used if the degree of freedom of accuracy is large.

  An insulating second cover coat 66 made of a second insulating epoxy resin (for example, Asahi Chemical Laboratory Co., Ltd. thermosetting solder resist CCR-232GF No. 6) is formed in each hole 65a of the first cover coat 65. Has been. The second cover coat 66 has a higher hardness than the first cover coat 65. The individual bump 136 of the actuator unit 21 is formed so as to protrude from the surface of the actuator unit 21, and the tip thereof penetrates the second cover coat 66 and is joined to the land 58. Although the protruding height of the individual bump 136 is larger than the depth of the hole 65a, a part of the second cover coat 66 reaches the surface of the actuator unit 21 from the base end portion of the individual bump 136 as shown in FIG. ing. A slight gap is formed between the actuator unit 21 and the first cover coat 65, and the unimorph deformation of the actuator unit 21 is not inhibited by the COF 50. Thus, since each individual bump 136 is surrounded by the second cover coat 66, it is possible to prevent a conductive foreign matter from entering between adjacent individual bumps 136 and short-circuiting. Further, since the second cover coat 66 has a high hardness, a stable electrical connection between the land 58 and the individual bump 136 can be maintained.

  A wiring region 61 is formed adjacent to the land region 60 on the surface of the substrate 51. In the wiring area 61, a mounting land on which the driver IC 52 is mounted is arranged as a wiring pattern 59 in addition to the plurality of wirings 59a and 59b. The wiring 59a connects the corresponding land 58 and the mounting land, and the wiring 59b connects the mounting land and the terminal 50a. An insulating solder resist (third coating layer) 67 made of a third insulating epoxy resin (for example, Nippon Polytech Co., Ltd. COF thermosetting solder mask NPR-3300) is formed on the wiring region 61. In the center of the solder resist 67, a hole 67a in which the driver IC 52 is disposed is formed. The ends of the wiring 59a and the wiring 59b are exposed in the hole 67a, thereby constituting a mounting land on the land 58 side and a mounting land on the terminal 50a side, respectively.

  Next, the manufacturing process of the inkjet head 1 will be described with reference to FIGS. As shown in FIG. 8, first, the head body 2 is manufactured (head body manufacturing process). Individual bumps 136 are formed on the surface of the actuator unit 21 so as to protrude from the lead-out end portions of the individual electrodes 135.

  Next, the COF 50 is manufactured. As shown in FIG. 8 and FIG. 9A, a plurality of lands 58 and wiring patterns 59 are formed on the base material 51 formed on the sheet material (other areas of the sheet material are not shown). And wiring pattern forming step). For example, a base material 51 on which a copper thin film is formed is prepared, and the copper thin film is processed into a predetermined form (a plurality of lands 58 and wiring patterns 59) by etching.

  Next, as shown in FIGS. 8 and 9B, a thermosetting third insulating epoxy resin is printed on the wiring region 61 including the wiring pattern 59 (third thermosetting epoxy resin coating step). . At this time, printing is performed leaving the hole 67a. And the printed 3rd insulating epoxy resin is heat-processed (120 degreeC), and it hardens | cures completely, and forms the solder resist 67 (solder resist formation process). The solder resist 67 covers a part of the wiring 59a (part not covered with the first cover coat 65) and the wiring 59b in the wiring pattern 59. The mounting land is exposed in the hole 67a. Thereafter, as shown in FIGS. 8 and 9C, the driver IC 52 is mounted on the mounting land in the wiring region 61 (driver IC mounting step).

  Next, as shown in FIGS. 8 and 10A, a thermosetting first insulating epoxy resin is screen-printed on the land region 60 (first thermosetting epoxy resin printing step). And the printed 1st insulating epoxy resin is heat-processed, and it hardens | cures completely, and forms the 1st cover coat 65 (1st cover coat formation process). The first cover coat 65 covers the land 58 except for the land 58 and the periphery of the land 58. At this time, the land 58 and its periphery are exposed in a hole 65 a formed in the first cover coat 65.

  Next, as shown in FIG. 8 and FIG. 10B, screen printing of a thermosetting second insulating epoxy resin is performed in each hole 65 a of the first cover coat 65 (second thermosetting resin printing). Process). Then, the second cover coat 66 is heat-treated (50 ° C.) at a temperature lower than that of the above-described heat treatment to be in a semi-cured state (semi-curing step). Thereby, the semi-cured second cover coat 66 covers the lands 58 and the periphery of the lands 58. By setting the second cover coat 66 in a semi-cured state, the epoxy resin is not freely spread, and the handleability is improved.

  Thereafter, the base material 51 is punched from the sheet material (base material punching step). And the terminal 50a is connected to the edge part of the base material 51, and COF50 is completed.

  Then, as shown in FIGS. 8 and 11A, the actuator unit 21 and the land region 60 of the COF 50 face each other. At this time, the individual bump 136 and the land 58 are arranged to face each other. Further, as shown in FIG. 11 (b), the two bumps 136 are pressed while being brought close to each other, and the individual bumps 136 are brought into contact with the lands 58 while penetrating the semi-cured second cover coat 66.

  In this state, by applying heat and pressure treatment (150 ° C.), the second cover coat 66 is completely cured, and the individual bumps 136 and the lands 58 that are in contact with each other are electrically joined. At this time, the second cover coat 66 surrounds the entire circumference of the joint portion between the individual bump 136 and the land 58. In addition, when the second cover coat 66 is completely cured, the individual bumps 136 and the lands 58 are firmly fixed (a heat and pressure bonding process (arrangement process) and a second cover coat formation process).

  As described above, according to the method of manufacturing the inkjet head 1 of the present embodiment, the land 58 in the base material 51 except the land 58 and the area around the land 58 is covered with the hardened first cover coat 65. Therefore, in the heat and pressure bonding process, even if the COF 50 is curved and the first cover coat 65 contacts the surface of the actuator unit 21, a part of the first cover coat 65 may adhere to the surface of the actuator unit 21. Absent. Thereby, it can suppress that the motion of the actuator unit 21 is inhibited. In addition, since the conductive foreign matter does not penetrate the first cover coat 65, the conductive foreign matter comes into contact with the wiring 59a drawn from the land 58 in the land region 60 to cause a short circuit or damage to the wiring 59a. Can be suppressed.

  In addition, since the second cover coat 66 is in a semi-cured state when the heat and pressure bonding process is performed, the second insulating epoxy resin that is the second cover coat 66 stays around the lands 58 and the lands 58. It becomes easy and it is suppressed that it moves to other places or falls. Thereby, the 2nd cover coat 66 of a desired form can be formed easily.

  Furthermore, since heat treatment is performed in the first cover coat forming step, the semi-curing step, and the second cover coat forming step, the manufacturing cost can be reduced.

  Moreover, since the height from the surface of the base material 51 which concerns on the 1st cover coat 65 is higher than the land 58, when performing a heating-pressing joining process, the base material 51 is made into the plane of the actuator unit 21. On the other hand, it can press with a uniform pressure. Thereby, the individual bump 136 and the land 58 can be reliably brought into contact with each other.

  In addition, since the solder resist 67 covers the wiring pattern 59 by performing the solder resist forming step, a conductive foreign matter adheres between the wirings related to the wiring pattern 59 and short-circuits or the wiring is damaged. Can be suppressed.

  In addition, since the second cover coat 66 has a higher hardness than the first cover coat 65, the electrical bonding state between the individual bumps 136 and the lands 58 can be stabilized and the flexibility of the COF 50 can be prevented from being impaired. can do.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. In the above-described embodiment, the first insulating epoxy resin that is the material of the first cover coat 65, the second insulating epoxy resin that is the material of the second cover coat 66, and the third insulating epoxy that is the material of the solder resist 67. The resins are different materials, but at least two of these may be the same material. According to this, the manufacturing cost can be reduced. For example, the second insulating epoxy resin and the third insulating epoxy resin may be the same material. As mentioned above, the two resins are both fully cured before the semi-curing step. Therefore, by using these two resins as the same material, it is possible to perform printing on each region and heat treatment for complete curing at a time, thereby reducing the number of steps.

  In the above-described embodiment, the first cover coat 65, the second cover coat 66, and the solder resist 67 are formed using the first to third insulating epoxy resins, but have other insulating properties. These may be formed using materials.

  Furthermore, in the above-described embodiment, the second cover coat 66 is in a semi-cured state when performing the heat-pressure bonding process. The structure which performs a joining process may be sufficient. At this time, the second cover coat 66 is formed by the heat and pressure bonding process. According to this, the manufacturing cost can be reduced. In addition, from the viewpoint of eliminating unnecessary spread of the resin and improving the handleability, at least a second insulating epoxy resin having a viscosity higher than that of the first insulating epoxy resin may be printed.

  In addition, in the above-described embodiment, the heat treatment is performed in the solder resist forming process, the first cover coat forming process, the semi-curing process, and the second cover coat forming process, so that the solder resist 67 and the first cover coat 65 are processed. The second cover coat 66 (including a semi-cured state) is formed, and at least one of the solder resist, the first cover coat, and the second cover coat is formed by a method other than the heat treatment. Also good.

  In the above-described embodiment, the height of the individual bump 136 is larger than the depth of the hole 65a, but it may be substantially the same size. Since the first cover coat 65 is completely cured, the first cover coat 65 does not adhere to the surface of the actuator unit 21 in the arrangement process, and does not hinder the movement of the actuator unit 21.

  Furthermore, in the above-described embodiment, the solder resist 67 that covers the wiring pattern 59 is formed. However, the solder resist 67 may not be formed.

  In addition, in the above-described embodiment, the completely hardened second cover coat 66 has a higher hardness than the first cover coat 65, but the second cover coat has a hardness equal to or lower than the first cover coat. There may be.

  Furthermore, in the above-mentioned embodiment, although it is the structure which uses the unimoful type actuator unit 21, the structure which uses a bimorph type actuator unit may be sufficient, and a several separate land on a plane is 3x3 or more. As long as the configuration is distributed, a configuration using actuator units of other types may be used.

  In addition, in the above-described embodiment, in the second insulating epoxy resin printing step, the second insulating epoxy resin is screen-printed on the base 51, but the second insulating epoxy resin is the first cover. A configuration in which the second insulating epoxy resin is spread on the first cover coat 65 using a squeegee so as to fill each hole 65a of the coat 65 may be employed.

  The present invention is also applicable to a recording apparatus that ejects liquid other than ink. Further, the present invention is not limited to a printer, and can be applied to a facsimile, a copier, and the like.

DESCRIPTION OF SYMBOLS 1 Inkjet head 2 Head main body 9 Flow path unit 21 Actuator unit 50a Terminal 51 Base material 54 Control board 58 Land 59 Wiring pattern 60 Land area 61 Wiring area 65 First cover coat 65a Hole 66 Second cover coat 67 Solder resist 101 Inkjet printer 105a Sub-manifold channel 108 Discharge port 110 Pressure chamber 132 Individual ink channel 134 Common electrode 135 Individual electrode 136 Individual bump 141-143 Piezoelectric sheet 52 Driver IC

Claims (8)

A flow path unit in which a plurality of nozzles for discharging liquid are formed, an actuator for discharging liquid from the nozzle, the actuator having a plurality of individual bumps arranged on a plane, and the individual bumps of the actuator A manufacturing method of a recording head having a flat flexible substrate for supplying a driving signal,
A land forming step of forming a plurality of lands corresponding to the plurality of individual bumps on a surface of a base material to be the flat flexible substrate;
A first insulating material application step of applying a first insulating material so as to cover the land and the area excluding the periphery of the land among the land arrangement areas where the plurality of lands are arranged on the surface;
A first covering layer forming step of forming a first covering layer by curing the first insulating material;
A second insulating material application step of applying a second insulating material so as to cover the land and the periphery of the land in the land arrangement region where the first covering layer is formed;
An arrangement step of arranging the flat flexible substrate on the actuator so that the individual bumps penetrate the applied second insulating material and contact the land;
A recording head manufacturing method comprising: a second coating layer forming step of forming a second coating layer by curing the applied second insulating material after the arranging step. Prior to the placing step, the method further comprises a semi-curing step of semi-curing the applied second insulating material,
2. The method of manufacturing a recording head according to claim 1, wherein in the second coating layer forming step, the second coating layer is formed by curing the second insulating material in a semi-cured state. The first insulating material and the second insulating material have thermosetting properties;
In the first coating layer forming step, by heating the first insulating material, the first coating layer is formed,
In the semi-curing step, the second insulating material is semi-cured by heating the second insulating material,
3. The method of manufacturing a recording head according to claim 2, wherein in the second coating layer forming step, the second coating layer is formed by further heating the second insulating material in a semi-cured state. .   The method for manufacturing a recording head according to claim 1, wherein the first insulating material and the second insulating material are different from each other.   5. The recording head manufacturing method according to claim 1, wherein the first covering layer is higher than the land on the surface in a direction orthogonal to the surface. A pattern forming step of forming a plurality of wirings electrically connected to the land on the surface;
Prior to the placement step, a third insulation material application step for applying a third insulation material so as to cover a wiring region adjacent to the land placement region and where the plurality of wires are arranged on the surface;
6. The method according to claim 1, further comprising a third coating layer forming step of forming a third coating layer by curing the third insulating material prior to the arranging step. The manufacturing method of a recording head as described in an item.   The method for manufacturing a recording head according to claim 6, wherein the second insulating material and the third insulating material are the same material. A flow path unit having a plurality of nozzles for discharging liquid;
An actuator that discharges liquid from the nozzle, the actuator having a plurality of individual bumps arranged on a plane;
A flat flexible substrate fixed to the actuator and supplying a drive signal to the individual bumps,
The flat flexible substrate is
A substrate having a surface facing the plane, a plurality of lands disposed on the surface of the substrate and electrically bonded to the plurality of individual bumps, and a land arrangement region in which the plurality of lands are disposed An insulating first covering layer covering the land and a region excluding the periphery of the land, and an insulating second covering through which the individual bumps penetrate and cover the periphery of the land in the land arrangement region And has a layer,
The recording head according to claim 1, wherein the second coating layer has a higher hardness than the first coating layer.

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